| (19) |
 |
|
(11) |
EP 0 293 168 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
07.02.1990 Bulletin 1990/06 |
| (43) |
Date of publication A2: |
|
30.11.1988 Bulletin 1988/48 |
| (22) |
Date of filing: 24.05.1988 |
|
|
| (84) |
Designated Contracting States: |
|
DE FR GB IT |
| (30) |
Priority: |
26.05.1987 JP 126989/87
29.09.1987 JP 242715/87
14.04.1988 JP 90365/88
|
| (71) |
Applicant: NIPPON FURNACE KOGYO KAISHA LTD. |
|
Tsurumi-ku,
Yokohama-shi,
Kanagawa-ken 230 (JP) |
|
| (72) |
Inventor: |
|
- Kawamoto, Masao
Isogo
Isogo-ku
Yokohama-shi
Kanagawa-ken (JP)
|
| (74) |
Representative: Dealtry, Brian et al |
|
Eric Potter & Clarkson
St. Mary's Court
St. Mary's Gate
Nottingham NG1 1LE
Nottingham NG1 1LE (GB) |
|
| |
|
| (54) |
Furnace with a radiant tube burner assembly including a two stage fuel supply |
(57) The present invention relates to a low NOx radiant tube burner. The radiant tube
burner consists of; a primary combustion chamber (6) which is located outside of the
furnace (14) and having an injection outlet (21) of the combustion gas located approximately
more inside of the furnace (14) than the bung of the radiant tube (1), a primary fuel
nozzle (4) which injects primary fuel into the primary combustion chamber (6), and
a secondary fuel nozzle (7) which is surrounded with refractory material and injects
secondary fuel into the radiant tube (1) from the area adjacent to the injection outlet
(21). Approximately the total amount of the combustion air is supplied into the primary
combustion chamber (6) with primary fuel under a high excess air ratio creating primary
combustion. The low concentration of oxygen remaining in the primary combustion gas
combined with the secondary fuel creates secondary combustion.